I. Field of the Invention PA1 II. Description of the Prior Art
The present invention relates to an electrodeposition process for the preparation of precursor superconductor powders for subsequent use in the formation of superconductors.
The preparation of superconductor compositions requires the formation and treatment of complex metal oxides wherein the constituents therein are in an appropriate combination for superconducting properties. One example of such a metal oxide is thallium-barium-calcium-copper oxide (TBCCO), a high-temperature superconductor compound. Various methods have been taught for the preparation of superconductors. One such general methodology for preparing superconducting ceramics comprises the electrochemical deposition of a mixture of appropriate metals on a substrate, followed by oxidation of the deposited mixture into the superconducting ceramic. A related method comprises the sequential electrodeposition of layers of appropriate metals on a substrate, followed by oxidation of the deposited layers. Another approach involves suspending, dispersing or dissolving superconductor precursor components within a liquid medium, followed by electrodeposition on a substrate and subsequent oxidation of the entire mass. The preparation of components for such introduction into a liquid medium include a sol-gel process for producing precursor powders; a pyrolytic spray process wherein an atomized spray of metal nitrates is directed into a calcination zone for water vaporization and simultaneous conversion of the nitrates to oxide powders; a chemical co-precipitation process from multiple-salt solutions to produce a metallic powder; and a mechanical process wherein a superconductor material is subjected to manual grinding to thereby produce a powder.
While the effectiveness of employing a powder of superconductor precursor components for subsequent treatment is obviously recognized, the methodologies for preparing such powders are traditional and somewhat burdensome practices. Further, these prior art methods generally produce only a physical mixture of components rather than an amorphous product. Additionally, in the case of thallium, the prior art approaches do not lend themselves to the direct addition of this metal to an initial precursor formulation. Thus, mixing on an atomic scale is not achieved in the prior art.
It is therefore apparent that a need is present for an effective method of producing a precursor powder for subsequent treatment and conversion into a superconductor material. Accordingly, a primary object of the present invention is to provide a process for the production of a superconductor precursor powder employing a chemical electrodeposition of salts of metals capable of exhibiting superconductor characteristics, and thereafter recovering deposited compositions as a precursor powder.
Another object of the present invention is to provide a process for the production of a superconductor precursor powder employing metals capable of yielding a high temperature superconductor upon subsequent treatment.
Yet another object of the present invention is to provide a process for the production of a superconductor precursor powder from salts of thallium, barium, calcium and copper, with and without the inclusion of a salt of silver.
These and other objects of the present invention will become apparent throughout the description of the invention which now follows.